JPS6317552B2 - - Google Patents

Description

divider 12 Arc welding oscillation control device equipped with.

2 Welding voltage or welding current is kept constant by adjusting the welding voltage detection circuit 32 or welding current detection circuit and the welding torch height or welding electrode feeding speed according to the output of the welding voltage detection circuit or welding current detection circuit. an arc voltage tracing control circuit to maintain the arc voltage at a welding torch swing mechanism that reverses the driving direction based on a signal; a groove width calculation circuit that calculates the groove width based on the output signal of the groove edge detection circuit; and a welding torch that is inversely proportional to the output signal of the groove width calculation circuit. An arc welding oscillation control device comprising a welding speed control circuit 13 for obtaining speed.

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an improvement in an arc welding swing control device that performs arc welding while swinging a welding torch in a direction across a welding line.

[Prior art and problems to be solved] Conventionally, when welding is performed while swinging a welding torch, a welding line detector is provided and the welding torch is made to follow the welding line based on the output of this detector. A method has also been proposed in which the groove width is detected and the swing width of the welding torch is determined according to the groove width.

In the first conventional method, as shown in FIGS. 8 and 9, for example, when the groove width changes from W to W1=kW, the welding speed S and the moving speed of the torch following the swing trajectory ( Since the oscillation speed (hereinafter referred to as Y) is constant, the welding length for one period of the oscillation trajectory (hereinafter referred to as oscillation pitch) changes from P to P1, and the amount of welding per unit area also changes from D to D1. It has the disadvantage of changing. In other words, regardless of changes in the groove width, when the rocking speed Y and the welding speed S are constant, the time required for the torch to move across the groove width W is T1, and the amount of melting of the consumable electrode during that period is F, the welding length is L, and the swing area due to torch movement is M, the amount of welding per unit area D is: M=LW/2, T1=W/Y, L=S・T1 D=F/M= 2F/LW Next, when the groove width becomes W1=kW, let T2, F1, L1, and M1 be respectively, and the amount of welding D1 per unit area is T2=W1/Y L1=S・T2= (W1/W)L=kL F1=(T2/T1)F=(W1/W)F=kF M1=L1・W1/2=kL・kW/2=k ² LW/2 D1=F1/M1= kF/(k ² LW/2)=2F/
LW·k = D/k, and when the groove width W changes to W1=kW, the amount of welding per unit area decreases to 1/k.

Next, in the second conventional method, as shown in FIGS. 8 and 10, for example, the welding speed S is constant regardless of changes in the groove width, and the unit when the groove width is W is used. The amount of welding D per area is D=2F/LW, as described above.

Next, when the groove width becomes w1=kW, if the swing speed Y1 is changed to W1/W, the swing pitch P remains the same, but the unit area There is a drawback that the amount of welding per unit changes from D to D1. In other words, the welding speed is constant regardless of changes in the groove width, and the time required for the torch to move through the groove width w1 = kW is T3.
Assuming that the amount of melting of the consumable electrode during that period is F2, the welding length is L2, and the swing area due to torch movement is M2, the amount of welding per unit area D2 is: T3 = W1/Y1, Y1/Y = W1/W L2=S・T3=L(T3/T1)=L F2=(T3/T1)F M2=L2・W1/2=L・kW/2 D2=F2/M2=F/(kLW/2) =2F /LWk=D/k, and when the groove width W changes to W1=kW, the amount of welding per unit area decreases to 1/k.

[Means for Solving the Problem] The first invention includes a groove detector 8 that detects changes in the groove width and groove position, and a groove detector 8 that detects the position of the welding torch 6 in the swing direction and determines the torch position. A torch position detector 9 outputs a signal et, a groove width signal generator 11 outputs a groove width signal ew corresponding to the groove width in conjunction with the groove detector 8; A groove position signal generator 10 outputs a groove position signal ep corresponding to changes in the groove position in conjunction with a groove width signal ew, which outputs a waveform signal corresponding to a preset period, amplitude, and swing locus. an oscillating waveform signal oscillator 1 that oscillates the corrected waveform signal eo by correcting the waveform signal eo;
An adder 2 adds the groove position signal ep to the waveform signal eo and outputs the swing center correction waveform signal es, and compares the swing center correction waveform signal es and the torch position signal et to follow the waveform signal es. A torch oscillation waveform signal that commands the oscillation, stop, and oscillation direction of the welding torch.
Comparator 3 supplies ey to electric motor M1 for swinging the welding torch, and inputs the reference signal er corresponding to the relative movement speed between the welding torch and the workpiece and the groove width signal ew, and performs welding corresponding to the groove width. The present invention provides an arc welding oscillation control device that includes a divider 12 that supplies a speed signal so to a relative movement electric motor M2.

The second invention adjusts the welding torch height or welding electrode feeding speed according to the output of the welding voltage detection circuit 32 or the welding current detection circuit (not shown) and the welding voltage detection circuit or the welding current detection circuit. ,
an arc voltage tracing control circuit that keeps the welding voltage or welding current constant; a beveled edge detection circuit 33 that detects a sudden change in signal at the beveled edge of the output of the welding voltage detection circuit or welding current detection circuit; A welding torch swing mechanism that reverses the drive direction based on the output signal of the groove detection circuit, a groove width calculation circuit that calculates the groove width based on the output signal of the groove edge detection circuit, and a groove width calculation circuit that calculates the groove width based on the output signal of the groove width calculation circuit. An arc welding oscillation control device is provided which includes a welding speed control circuit 13 that obtains an inversely proportional welding speed.

[Example] (First invention) FIG. 1 is a block diagram showing an example of the present invention.
In the same figure, 1 is the swinging trajectory of the torch, the swinging width,
This is an oscillating waveform signal oscillator that outputs a waveform signal eo corresponding to the oscillation period. For example, as shown in the signal waveform diagram of FIG. 11, the amplitude wo, corresponding to the oscillation width,
Rise speed wo/2・t1 corresponding to swing speed Y,
Set the time (t2-t1) corresponding to the swing stop time. The amplitude of this oscillating waveform signal oscillator 1 is controlled by a groove width signal generator, such as a potentiometer 1, which will be described later.
Corrected by the output of 1. 2 is an adder, and 3 is a comparator, which outputs a sum or difference signal of two input signals, which will be described later. 4 is the output signal ey of comparator 3
This is an amplifier that amplifies and drives the welding torch swing electric motor M1. 6 is a welding torch, which is swung in a direction across the welding line by an electric motor M1.
8 is a groove detector that detects changes in groove width and groove position. 9 is a torch position detector that detects the position of the welding torch in the swinging direction and outputs a torch position signal et, and is, for example, a potentiometer; A groove position signal generator, such as a potentiometer, 11 that outputs a groove position signal ep corresponding to a change in position.
is a groove width signal generator, such as a potentiometer, which outputs a groove width signal ew corresponding to the groove width in conjunction with the groove detector 8. A divider 12 divides the reference signal er corresponding to the relative movement speed between the welding torch and the workpiece by the groove width signal ew to obtain a welding speed signal so=er/ew corresponding to the groove width. 13 is a welding speed control circuit for moving the welding torch relative to the workpiece 7 in the welding line direction, and rotates the electric motor M2 for relative movement of the welding torch and workpiece at a speed according to the welding speed signal so. let

Here, the principle of swinging operation of the torch when the groove width and groove position are constant, that is, the groove position signal ep and the groove width signal ew are constant, will be explained.

When the torch is at the center position A of the oscillation width W as shown in FIG. 8, and the oscillation waveform signal eo is at the time to as shown in FIG.
is the amplitude at time t1 from the position of amplitude O at time to
When it starts increasing towards wo/2, the groove width signal
Since ew is constant, the oscillating waveform signal oscillator 1 outputs a waveform signal eo with a maximum amplitude of wo/2. Since the groove position signal ep is also constant, the adder 2 also outputs the swing center correction waveform signal es with a constant maximum amplitude. When the amplitude of this waveform signal es increases, the torch oscillation waveform signal ey output from the comparator 3 is supplied to the oscillation motor M1 through the amplifier 4, and the torch moves from the oscillation center position A shown in FIG. 8 to the maximum oscillation. The torch starts to swing toward the position B of the swing width, and the torch position signal et of the each position detection potentiometer 9 also continues to increase in conjunction with the swing position of the torch. When the waveform signal eo reaches the maximum positive amplitude wo/2, the torch position signal et also reaches the maximum value, the signal ey=es−et becomes zero, and the torch stops at the position of the maximum swing width W. When time t2 elapses, the waveform signal eo begins to decrease from the maximum positive amplitude wo/2 to the maximum negative amplitude -wo/2, and a signal ey=et-es is generated and is transmitted through the amplifier 4 to the oscillating motor. Since the torch is supplied to M1, the torch starts swinging again from the maximum swing width position C toward the maximum swing width position E in the opposite direction. Similarly, as long as the groove position signal ep, the groove width signal ew, and the welding speed S are constant, the torch repeats an oscillation trajectory with a constant oscillation width and oscillation pitch.

(Explanation of waveforms in FIG. 2) The operation of the embodiment shown in FIG. 1 will be explained with reference to the waveform diagrams in FIGS. 2b to 2g. In this example, the groove shape of the workpiece to be welded is as shown in FIG. 2a, and the groove width shown by the solid line and the center position shown by the dotted line change as shown in the figure. At this time, oscillator 1
As the groove width signal ew of the groove width signal generator 11 changes as shown in FIG. 2b, a waveform signal eo having the peak value shown in FIG. 2c is generated. At this time, the amplitude and period of the waveform signal eo of the oscillator 1 change as shown in FIGS. 11 and 12 due to changes in the groove width. This waveform signal eo of oscillator 1 and the second
The groove position signal ep shown in FIG. d is added by the adder 2 to produce the swing center correction waveform signal es shown in the figure e. This signal es is compared with the welding torch position signal et by the comparator 3, and the oscillating motor M1 is rotated via the amplifier 4 to drive the torch so that both outputs are balanced. The torch oscillates following the correction waveform signal es from the adder. At this time, since the slope of the oscillation waveform of the output signal of the oscillator 1 is constant wo/2t as shown in FIGS. 11 and 12,
The swing speed Y of the torch that follows the waveform remains constant regardless of the swing width. The groove width signal ew is also supplied to the input terminal of the divider 12, and the reference signal er is divided by the groove width signal ew to obtain a signal that is inversely proportional to the groove width, as shown in FIG. Welding speed signal so=er/
get ew. This speed signal so is input to the welding speed control circuit 13, and the welding speed is fast where the groove width is narrow and slow where the groove width is wide.
FIG. 2g is a diagram showing the oscillation locus of the torch, and the oscillation width changes in accordance with the groove width.

Next, it will be explained that in the welding method of the present invention, the amount of welding per unit area can be kept constant even if the groove width changes. Bevel width is W
In this case, as explained in FIG. 8, the amount of welding D per unit area is D=F/M=2F/
It is Lw. Note that the time T1 required for the torch to move across the groove width W is W/Y.

Next, when the groove width changes to w1=kW,
When the swing speed Y is kept constant and the welding speed S3 is set to (W/W1)S, the time required for the torch to move across the groove width W1 is T4=W1/
Assuming that Y, the amount of melting of the consumable electrode is F3, the welding length is L3, and the swing area due to the movement of the torch is M3, the amount of welding per unit area D3 is as shown in Figure 13, Y=W/T1=W1/ T4 T4=(W1/W)・T1=k・T1 S3=(W/W1)S=S/k L=S・T1 L3=S3・T4=(S/k)・kT1=S・T1=L F3=(T4/T1)F=(W1/W)F=kF M3=L3・W1/2=L・kW/2 D3=F3/M3=kF/(L・kW/2)=2F/
LW=D, and even if the groove width increases from W to W1, the amount of welding per unit area does not change.

(Description of the groove detector shown in FIG. 3) FIG. 3 is a diagram showing an example of the groove detector used in the embodiment of FIG. 1. In the figure, 801 is an abacus bead-shaped detection wheel that comes into contact with both shoulders of the groove 701 of the workpieces 7, 7, and the detection wheel 801 moves in the Y direction in the figure while being restrained by a guide block 804. It is pivotally supported by a freely movable guide bar 802 and biased in the Y direction by a spring 803. 11 is Y of the detection wheel
This potentiometer converts directional displacement into an electrical signal, and its shaft 111 is supported by a guide bar 802 and a joint 805 at its tip. 8
06 is a slider that is guided by guide bars 807, 807 and is movable in the X direction in the figure.
A guide block 804 is supported. 10 is a potentiometer that converts the change in the X direction of the detection wheel 801 into an electric signal, and the slider 8
06 supports a shaft 101. A guide block 809 restrains the guide bar 807, and is fixed to the cart 15 carrying a welding torch and traveling on a predetermined track. 808, 808 are springs for biasing the slider 806 in the X direction. In the device shown in the figure, when the width of the groove 701 changes, the detection wheel 801 moves in the Y direction in the figure, and as a result, the output of the potentiometer 11 increases or decreases, indicating that the width increases or decreases. On the other hand, when the groove position is meandering, the detection wheel 801 moves in the X direction in the figure, and the output of the potentiometer 10 increases or decreases, indicating the displacement of the groove center.

In the groove detector shown in Fig. 3, an example was shown in which the groove position is determined by detecting the displacement of the detection wheel in the X direction.
Another method for detecting the bevel tip is to provide a contact that swings together with the welding torch, and use a limit switch, proximity switch, or other method to detect the contact of this contact with the shoulder of the bevel.
The rocking direction may be reversed. In this case, the oscillator 1 in the embodiment of FIG. 3 is set to always increase (or decrease) with a constant slope over time, and the above-mentioned open end detection signal is used to
What is necessary is to switch from increase to decrease (or from decrease to increase). Furthermore, the groove width does not depend on the position of the detection wheel in the X direction in Fig. 2, but rather from the time when the groove edge detection signal described above is generated to when another groove edge is reached and detected. The swinging distance between the two positions may be calculated by integrating the swinging time or the amount of movement of the swinging axis.

(Description of the groove detector shown in FIG. 4) FIG. 4 is a diagram showing another embodiment of the groove detector. The figure has a scissor-like link mechanism with two contacts that contact both shoulders of the groove at the tip. The groove width is detected by the amount of opening of this link mechanism, and the groove width is detected by the position of the link mechanism. This is to detect the previous position. Figure a is a front view including a partial cross section, and figure b is a side view. In the same figure, reference numerals 16 and 16 refer to contacts 1 whose tips slide while contacting both shoulders of the bevel;
7 and 17 are scissor-like link mechanisms supported by the fulcrum pin 21 of the slider 26 and constantly urged outward by a spring 18. Link mechanism 17, 17
Further, the slider 2 supporting the fulcrum pin 19
8. It is supported by a guide bar 29 so that it can expand and contract in the Y direction in the figure. A potentiometer 11 is attached to the connecting pins 20, 20 of the link mechanisms 17, 17, and the distance between the connecting pins is converted into an electric signal, which becomes a groove width signal. Furthermore, link mechanism 1
A slider 26 supporting the sliders 7 and 17 is guided by guide bars 27 and 27 and is supported movably in the X direction in the figure. The movement of the slider 26 is controlled by a rack 25 attached to the frame 30 of the detector.
The pinion gear 24 at the shaft end of the rotary potentiometer 10 attached to the slider 26 converts the signal into an electric signal, which becomes a bevel position signal. This detector, like the detector shown in FIG. 3, is supported by a welding cart (not shown). When using the detector shown in the figure, when the groove width becomes wider (or narrower), the interval between the contacts 16, 16 becomes wider (narrower).
As a result, the interval between the connecting pins 20, 20 of the link mechanisms 17, 17 becomes narrower (or wider), and the output of the potentiometer 11 that detects the interval between the connecting pins 20, 20 increases or decreases. Further, when the bevel position is meandering, the link mechanisms 17, 17 are supported by the slider 26 by the fulcrum pins 19, 21, and the slider 26 is supported by the guide bars 27, 27.
Since the direction of movement is restricted by
This movement is converted into a rotation angle by the rack 25 and pinion gear 24, and the output of the rotary potentiometer 10 is increased or decreased.

In the embodiments shown in Figs. 3 and 4, a potentiometer was used as a means to convert the groove position and groove width into electrical signals, but in addition to this, a differential transformer and a pulse converter for converting the amount of displacement were used. It is possible to replace it with a known equivalent, such as a digital position detector that counts the number of generated pulses. It is also possible to use those of these embodiments for only one of the groove width and the groove position, and use a limit switch or the like that directly detects the other.

(Second invention) In addition to detecting the groove width and groove position using a mechanical detector, it is also possible to detect the groove tip by detecting changes in welding voltage and welding current. Generally, when performing non-consumable electrode arc welding using a welding power source with constant current characteristics, the electrode height is controlled, and in consumable electrode arc welding, the feeding speed of the consumable electrode wire is controlled. It is controlled by voltage and adjusted to always maintain a constant welding voltage. Furthermore, when using a power source with constant voltage characteristics, the wire feeding speed is kept constant, the arc length is constant due to the self-controllability of the arc, and the welding current is also kept at a constant value. Even in a welding machine where the welding voltage or welding current is automatically controlled to be kept constant, when the welding torch is oscillated in the width direction of the groove, it is necessary to Since the shape changes suddenly, the time corresponding to the response delay time of the control system is
A change appears in the welding voltage or welding current.

(Explanation of Fig. 5) Fig. 5 shows the situation at this time. Fig. 5 a shows the groove shape of the workpiece, and Fig. 5 b shows the welding voltage when using a power source with constant current characteristics. Figure c shows the state of current when using a power supply with constant voltage characteristics. In the figure, 7 and 7 are objects to be welded, 701 is an I-shaped groove, and 702 is a backing. Welding is performed on this groove portion while the welding torch 6 swings in the left-right direction in the figure. At this time, when the torch 6 approaches the end of the groove 701, the arc length suddenly shortens, as shown in b and c in the same figure.
As shown at t ₁ and t ₂ , a drop in welding voltage or a sudden increase in welding current occurs. This sudden change in the welding condition is caused by
Although it is immediately corrected by the automatic control function described above, it takes some time Δt during this time due to the delay in response of the system. Therefore, by detecting the change in welding voltage or current during this period of Δt and using this as a signal to reach the open end, it is possible to know the welding torch oscillation width. Furthermore, the groove width can be determined by calculating the swinging distance that the welding torch moves between times _t1 and _t2 in FIGS. 5b and 5c.

(Explanation of FIG. 6) FIG. 6 is a block diagram showing an embodiment of the second invention, and shows an apparatus using non-consumable electrodes. In the figure, a welding power source S with constant current characteristics is connected between a welding torch 6 and a workpiece 7. The voltage between the welding torch 6 and the workpiece 7 is
The welding voltage detection circuit 32 detects the voltage and outputs a voltage detection signal ea. This voltage detection signal ea is compared with a reference voltage erl corresponding to the welding torch height in a comparator Comp1, and after being amplified by an amplifier Amp1, the welding torch 6 is adjusted so that the difference signal becomes zero.
The torch height adjustment electric motor M3 is driven to adjust the height of the torch. This welding voltage detection circuit 32, comparator Comp1, amplifier Amp1, and electric motor M3 constitute an arc voltage tracing control circuit for keeping the welding voltage constant. On the other hand, welding voltage detection circuit
ea is also input to an open end detection circuit 33 that detects sudden changes in welding voltage. The open end detection circuit is
It detects a sudden change in welding voltage, and for example, as shown in FIG.
A comparator that compares and outputs the difference signal el between both signals.
A circuit consisting of a comparator Comp3 and a comparator Comp4 that compares the difference signal e1 with a reference signal er4 outputs a signal when the amount of change in the input signal exceeds a certain amount (reference signal er4). in this case,
If the input/output characteristics of the comparator Comp3 have a certain dead zone, the comparator Comp4 and the reference signal er4 can be omitted. It goes without saying that the dead zone of the reference signal er4 or the comparator Comp3 is selected to a value that covers the variation in the arc voltage inside the groove. In this way, the groove edge detection circuit 33 generates a pulse-like output with a time width Δt in FIG. 5 when the welding voltage suddenly changes at both ends of the groove. This output is supplied to the swing direction switching circuit 34. The swinging direction switching circuit 34 is also supplied with the output signal er3 of the swinging speed setter 35, and each time the output pulse from the open end detection circuit 33 is supplied,
The polarity of the setting signal er3 is inverted and a setting signal with a different polarity is output to the comparator Comp2. Comparator Comp
2, the output ef from the generator TG that detects the rotation speed of the welding torch oscillating motor M1 is compared with the output signal er3 of the oscillating speed setting device 35, and the difference between the two signals is amplified by the amplifier Amp2. is supplied to electric motor M1, which receives signal ef and signal er3.
Rotate in the direction that decreases the difference. As a result, the welding torch 6 moves in the X direction in the figure in the groove 701 of the workpiece 7, and its speed becomes a constant speed corresponding to the output signal er3 of the oscillating speed setting device, and the moving direction performs a swinging motion that reverses each time it reaches the open end.

On the other hand, the output of the open end detection circuit 33 is also supplied to the monomulti 36 and the memory circuit 38. The monomulti 36 receives the output pulse of the groove edge detection circuit 33, converts the waveform into a rectangular pulse with a constant time width, and supplies the pulse to the groove width calculation circuit 37 as a calculation start signal. The groove width calculation circuit 37 is, for example, an integral circuit, which is reset by the falling signal of the output pulse of the monomulti 36, and is a generator that detects the rotational speed of the welding torch oscillating electric motor M1.
Integration of the output of the TG is started, and the integration is stopped at the rising edge signal of the next output pulse of the monomulti 36. The output of the groove width calculation circuit 37 is input to the memory circuit 8, and the memory circuit 38 is configured so that the stored contents are rewritten by the output pulse of the groove edge detection circuit 33. With this configuration, the storage circuit 38 stores the output value of the groove width calculation circuit 37, which is obtained by integrating the output of the speed detection generator TG from time t ₁ to t ₂ in FIG. , holds that value until the next groove width detection pulse signal arrives. Since the output of the generator TG is proportional to the swinging speed of the welding torch 6, this integral value corresponds to the swinging distance, that is, the groove width. This groove width signal is divided by the reference signal er2 in the divider 12 to become the welding speed signal so, and the welding speed control circuit 13
is activated to rotate the relative movement electric motor M2 at a speed inversely proportional to the groove width.

In the embodiment shown in Fig. 6, the welding voltage is detected to control the welding torch height to be kept constant, and groove tracing is performed by detecting the groove tip and groove width based on changes in the welding voltage. At the same time, since the welding speed is controlled in inverse proportion to the groove width, uniform penetration and weld bead pattern can always be obtained even if the weld line changes three-dimensionally. Furthermore, the sixth
In the figure, only the reversal of the swinging direction is performed by the groove edge detection circuit 33, and the groove width is determined as shown in Figure 3 or 4.
It may be configured to be detected by the detector described in the figure.

Furthermore, it is also possible to apply consumable electrode arc welding to the embodiment shown in FIG. 6, in which case the welding torch height is constant and the electric motor M3
Furthermore, in consumable electrode arc welding using a constant voltage welding power source, the electrode wire is fed at a constant speed that provides the necessary welding current. A similar effect can be obtained by detecting a change in welding current instead of voltage and using it as the open end arrival signal.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform rocking welding by reliably following the welding torch along the groove, and by setting the welding speed to be inversely proportional to the groove width. , the amount of welding per unit area is always constant regardless of changes in groove width and groove position.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of the first invention, Fig. 2 is a diagram showing waveforms of each part of the embodiment of Fig. 1, and Figs. 3 and 4 are diagrams showing an embodiment of the groove detector. FIG. 5 is a diagram of voltage and current waveforms when welding while swinging in the groove, FIG. 6 is a schematic configuration diagram showing an embodiment of the second invention, and FIG. 7 is a diagram of the sixth embodiment. A configuration diagram showing an embodiment of the groove edge detection circuit used in the embodiment shown in the figure, FIG. 8 is a diagram showing the swing locus when the groove width is W, and FIGS. 9 and 10 are groove widths. is w1
Fig. 11 shows the waveform signal when the groove width is W, and Fig. 12 shows the waveform signal when the groove width changes to w1. FIG. 13 is a diagram showing a swing locus according to the method of the present invention when the groove width changes to w1. 1... Oscillating waveform signal oscillator, 2... Adder, 3
... Comparator, 6 ... Welding torch, 7 ... Workpiece, 8 ... Groove detector, 9 ... Torch position detector, 10 ... Groove position signal generator, 11 ... Groove width signal Generator, 12... Divider, 13... Welding speed control circuit, M1... Electric motor for welding torch oscillation, M2
...Electric motor for relative movement of welding torch and workpiece, 3
3... Groove tip detection circuit, 37... Groove width calculation circuit, eo... Waveform signal, et... Torch position signal,
ew...Gun width signal, ep...Gun position signal, es...
...Swinging center correction waveform signal, ey...Torch swinging waveform signal, so...Welding speed signal, er...Reference signal corresponding to the relative movement speed between the welding torch and the workpiece, W...Before fluctuation Groove width, W1...Group width after variation (W1=k・W), L...Torch changes groove width W
Welding length when moving, L1, L2, L3...
Welding length when the torch moves through the groove width W1, M
...Torch swing area when the torch moves through the groove width W, M1, M2, M3...The torch moves through the groove width W
Torch swing area when moving 1, Y, y1...
...oscillation speed.

Claims (1)

[Claims] 1. A groove detector 8 that detects changes in the groove width and groove position, and a torch position detector that detects the position of the welding torch 6 in the swing direction and outputs a torch position signal et. 9, and a groove width signal generator 11 that outputs a groove width signal ew corresponding to the groove width in conjunction with the groove detector 8.
, a groove position signal generator 10 that outputs a groove position signal ep corresponding to a change in the groove position in conjunction with the groove detector 8; an oscillating waveform signal oscillator 1 that corrects a waveform signal using the groove width signal ew and oscillates the corrected waveform signal eo; adding the groove position signal ep to the waveform signal eo; an adder 2 that outputs a swing center correction waveform signal es; and an adder 2 that compares the swing center correction waveform signal es with the torch position signal et and causes the welding torch to swing, stop, and swing in accordance with the waveform signal es. The torch oscillation waveform signal ey that commands the direction of movement is sent to the electric motor M for oscillating the welding torch.
1, a reference signal er corresponding to the relative moving speed between the welding torch and the workpiece, and the groove width signal ew are input, and a welding speed signal so corresponding to the groove width is input to the Supplied to mobile electric motor M2